Primary electric cell



Patented Oct. 16, 1951 y 1; PRIMARY ELECTRIC CELL Richard Walter Lewis and Alfred Linton, Hawkhill, Dundee, Scotland, assignors to Burndept Limited, London, England, a company of Great Britain Application May 28, 1948, Serial No. 29,887

(Cl. 13G-107) 6 Claims. l

This invention relates to the construction of primary electric cells, and especially of cells such as those employing the system HgO/KOI-I/Zn, which need a negative electrode of large surface area if a substantial ampere hour output is to be got from a cell of moderate dimensions.

According to this invention the cell is built within a zinc can which for-ms both its container and a part of its negative electrode. The positive electrode is surrounded by a conductive bobbin of mercurio oxide supported out of contact with the can. The space between the dolly thus consttuted and the zinc can is iilled with a roll of zinc-coated bibulous sheet material.

This sheet material is prepared by spraying, brushing or rolling on to a bibulous paper base a suspension of zinc-mercury amalgam in starch and water and then drying. The paper may be coated on one surface only which is made the outer surface in the roll, so that metallic contact is established between the coating and the container` while the bibulous paper separates the coating from the dolly. Moreover the dolly itself is preferably wrapped in bibulous paper, tied about the bobbin and about the positive electrode projecting from it. The cell assembled in its container is placed in a vessel which is evacuated and then caustic potash solution is admitted to the zinc container. This causes the paper to swell and the outermost turn of the roll to make good contact with the zinc can.

It has been proposed before to use a zinccoated paper roll as part of the negative electrode of a mercurio oxide cell.

A construction of electric dry cell according to the invention is illustrated in the accompanying drawings in axial section in Figure l and in transverse section on the line II-II of Figure 1 in Figure 2.

The zinc container is indicated at I. It is sheathed in a tube of insulating plastic 2 preferably of polyvinyl chloride. A carbon or iron rod 3 constitutes the positive electrode and extends through and projects from a conductive bobbin 4 of mercuric oxide and carbon. The bobbin may be wrapped in bibulous paper 5 tied about the bobbin and about the electrode 3. A cardboard or like disc 6 prevents the bobbin from contacting with the bottom of the container I. A paper roll 'I of several turns having a zinc coating 8 fills the space between the bobbin 4 and the can I.

Above the bobbin is a disc 9 of cardboard or the like. Upon this is poured a sealing compound I0, such as a layer of petroleum jelly. The end of the tubular sheathing 2 is turned over the lip of the can I. A metal cap I I closes the mouth of the can and is held in contact with the electrode 3 by the spinning inward of the insulated lip of the can.

We claim:

1. A primary electric cell comprising a zinc can forming both the container of the cell and a part of its negative electrode, a positive electrode surrounded by a conductive bobbin of mercurio oxide supported out of contact with said container, and a roll of zinc-coated bibulous sheet material lling the space between the dolly and the can, its coating being in conductive connection with the can.

2. A zinc-coated bibulous sheet to serve as the negative electrode of a primary electric cell consisting of a bibulous paper base having thereon a coating of a dry suspension of zinc-mercury amalgam in starch.

3. A method of preparing a zinc-coated bibulous sheet to serve as the negative electrode of a primary cell which consists in preparing a suspension of zinc-mercury amalgam in starch and water, spreading it upon a bibulous paper sheet by spraying, brushing or rolling, and then drying the sheet and winding it into a roll.

4. A primary electric cell comprising a zinc can forming both the container of the cell and a part of its negative electrode, a positive electrode surrounded by a conductive bobbin of mercuric oxide supported out of contact with said container, a roll of bibulous sheet material filling the space between the dolly and the can, and a suspension of Zinc in starch coating at least the outer sur- Y face of said material, said coating being in conductive connection with the can.

5. A primary electric cell comprising a zinc can forming both the container of the cell and a part of its negative electrode, a positive electrode surrounded by a conductive bobbin of mercuric oxide supported out of contact with said container, a sheet of bibulous paper having a coating of a suspension of zinc-mercurio amalgam in starch covering at least one surface thereof wound about said bobbin, its coating being in contact with said container, a tubular insulating sheathing wrapping the container, and reected over the lip of the container, and a metal cap closing the mouth of the container and held in contact with the positive electrode by the inturned sheathed lip of the container.

6. A primary electric cell comprising a zinc can v rounded by a conductive bobbin of mercuric oxide supported out of contact with said container, and a pervious suspension of zinc supported by fibrous material lling the space between said bobbin and the can.

RICHARD WALTER LEWIS. ALFRED LINTON.

REFERENCES CITED The following references are of record in the 10 le of this patent:

Number Number UNITED STATES PATENTS Name Date Lawson Jan. 5, 1943 Ruben ..1 June 10, 1947 Schmelzer July 13, 1948 FOREIGN PATENTS Country Date Great Britain of 1886 Great Britain Sept. 29, 1927 Great Britain Dec. 9, 1937 

1. A PRIMARY ELECTRIC CELL COMPRISING A ZINC CAN FORMING BOTH THE CONTAINER OF THE CELL AND A PART OF ITS NEGATIVE ELECTRODE, A POSITIVE ELECTRODE SURROUNDED BY A CONDUCTIVE BOBBIN OF MERCURIC OXIDE SUPPORTED OUT OF CONTACT WITH SAID CONTAINER, AND A ROLL OF ZINC-COATED BIBULOUS SHEET MATERIAL FILLING 